docs: def extract_realizations(dstore, dummy):
      """
      Extract an array of realizations. Use it as /extract/realizations
      """
      rlzs = dstore['csm_info'].rlzs
      dt = [('ordinal', U32), ('weight', F32), ('gsims', '<S64')]
      arr = numpy.zeros(len(rlzs), dt)
      arr['ordinal'] = rlzs['ordinal']
      arr['weight'] = rlzs['weight']
      arr['gsims'] = rlzs['branch_path']  # this is used in scenario by QGIS
      return arr